A method is known for three-phase autoreclosing of a transmission line after a short circuit at the line is cleared by the three phases opening from both ends, as discussed for example in P. Kundur, Power System Stability and Control (McGraw-Hill, Inc. 1994). The line is closed in all three phases from both ends after a pre-selected time interval. This time interval is chosen to guarantee that the secondary arc will self-extinguish. This method's disadvantage is lack of reliable information about the status of the opened faulted line and overly high probability of closing into a still-existing fault.
A method is known for single-phase autoreclosing at a transmission line, where for single phase to ground faults, the affected phase is identified and opened from both sides. Then amplitude of the induced voltage at the open phase is measured. If this amplitude exceeds a pre-selected value, the secondary arc is considered self extinguished and the opened phase is closed. This method is discussed in Soviet Union Inventor's Certificate No. 1,092,642 to Il' in et al., published May 15, 1984. This method's disadvantages are difficulties with detection of self extinguishing of the secondary arc for transmission lines which are heavily loaded, long, and not compensated.
A method is known for the single phase autoreclosing of a non-compensated transmission line where after the faulted is detected, the faulted phase is disconnected from both ends of the line. Then the angle between the voltage induced at the open phase and a reference phasor of the transmission line's zero-sequence current is measured. The faulted phase is closed if the angle exceeds the predetermined setting.
This method, like the previous one, does not work for three phase autoreclosing.
A method is known for three phase autoreclosing, where after the type of fault and status of the secondary arc are identified, the line is opened from both sides. Then for two phase faults the healthy phase is closed with the purpose of inducing voltages at the faulted phases. When the secondary arc is self extinguished in at least at one of faulted, phases this phase is closed from both ends. The remaining phase's condition is monitored and it is closed after its secondary arc self extinguishes. This method is described in Soviet Union Inventor's Certificate No. 1,042,121 to Basilevich et al., published Sep. 15, 1983.
This method's disadvantage is temporary operation with some phases of the transmission line out of service. It requires special adjustment of zero and negative sequence relay protection and additional delay for autoreclosing. The method is not applicable for three-phase short circuit conditions for sub transmission and distribution lines where circuit breakers typically do not have a single pole operation option.